The IRS is losing its dogged leader at a crucial time in the agency’s history

IRS Commissioner John Koskinen is reportedly stepping down as soon as tomorrow. His departure comes at a critical time — the IRS is underfunded and understaffed, just as Congress is gearing up to pass a massive tax overhaul.

Nancy Marshall-Genzer is a senior reporter for Marketplace, working from the Washington, D.C. Bureau. Nancy started with Marketplace in spring 2007, after filing freelance pieces for the program for years prior. Covering the daily news from the nation’s capital, Nancy has...